U.S. Pat. No. 5,078,165 patented on: Jan. 7, 1992 entitled: "Automatic Umbrella Opened and Closed by a Straightforward Push Button" invented by T. Z. Wu discloses a straightforward single push button 51 for controlling the opening and closing of the umbrella, which however may still have the following drawbacks:
1. The extending spring 3 is telescopically operated within the lower tubular shaft 11 and the upper tubular shaft 14 having a diameter larger than that of the lower shaft 11 so that there will have a large aperture between the coil spring 3 and an inside wall of the upper shaft 14. The spring 14 reciprocating within the aperture in the upper shaft 14 will exert noise due to a frictional contacting between the spring coils and the upper shaft 14.
2. Even a lower flange 143 is formed on the upper shaft 14 slidably held on the lower shaft 11 will bias the two helical springs 531a sidewardly as shown in FIG. 8 of prior art to form an aperture D between the two separated springs 531a, which aperture D is greater than a width W of the push button 51 so that during the depression of the push button 51 to open the umbrella, the inward movement of the button 51 will not depress the two springs 531a to prevent a false actuation of the closing controller 53 to ensure the locking of the locking head 536 by the retarding plate 533 of the closing controller 53.
However, if the push button 51 is further deeply depressed inwardly, the two springs 531a may still be touched and depressed to falsely actuate the closing controller 53 to unexpectedly accidentally close an opened umbrella.
The present inventors have found the drawbacks of the conventional prior art and invented the present automatic umbrella for improving the shortcomings of the prior art.